Control apparatus with timing means for refrigeration systems



R. D. MORGAN Jan. 17, 1967 CONTROL APPARATUS WITH TIMING MEANS FORREFRIGERATION SYSTEMS FIG. I

INVENTOR.

ROBERT D. MORGAN. BYz/ JWM ATTORNEY.

United States Patent M ware Filed July 1, 1965, Ser. No. 468,837 9Claims. (Cl. 62158) This invention relates to a refrigeration system,and more particularly, to a control arrangement for the compressor ofthe refrigeration system.

Refrigeration systems usually incorporate one or more protectivedevices, each effective at a certain malfunction in the system or thesystem compressor to render the compressor inoperative. Typicalprotective devices are, for example, an overtemp-erature sensor for thecompressor motor windings, system pressure measuring devices, devicesfor sensing adequate compressor oil pressure, etc. On stoppage of thesystem compressor, whether as a result of a malfunction or, morecommonly, the satisfaction of demand on the system, it is desirable thatimmediate restarting of the compressor be precluded.

In refrigeration systems which incorporate a control to preventimmediate restarting of the system compressor or compressors afterstoppage thereof, where the compressor stoppage is due to a prevailingsystem or compressor malfunction, the compressor or compressors arenevertheless restarted, subject to the control imposed delay,indefinitely until the operator becomes cognizant of the systemmalfunction or the compressor becomes totally inoperative This situationis of particular concern in commercial systems where the system is aptto be left unattended for prolonged periods of time.

It is a principal object of the present invention to provide a new andimproved control arrangement for refrigeration system compressors.

It is a further object of the present invention to provide a controlarrangement effective to limit the number of compressor restarts thatmay be made within a predetermined period of time.

It is an object of the present invention to provide, in conjunction witha control for delaying restart of a compressor for a timed intervalsubsequent to each deenergization thereof, an apparatus effective torender the restarting control inoperative following a predeterminednumber of compressor restarts within a given period of time.

It is an object of the present invention to provide an apparatus whichcounts each deenergization of a refrigeration system compressor,effective, following a preset number of compressor deenergizations in agiven period of time, to prevent further operation of the compressor.

It is a further object of the present invention to provide, in anapparatus for limiting the number. of compressor restarts in a givenperiod of time to a predetermined number, means for automaticallyresetting the apparatus following the successful operation of thecompressor.

The invention relates to a refrigeration system comprising incombination, a compressor, control means operable upon demand toenergize the compressor; condition sensing means operable upon theoccurrence of a predetermined malfunction to deenergize the compressor;timing means for preventing ree-nergization of the compress-or by thecontrol means for a timed interval following each deenergizationthereof; and means responding to a predetermined number of compressordeenergizations in the timed interval to render the control meansinoperative. '4

Other objects and advantages will be apparent from the ensuingdescription and the accompanying drawings in which:

FIGURE 1 is a schematic representation of a refrigeration systemincorporating the compressor control arrangement of the presentinvention;

FIGURE 2 is a wiring diagram of the compressor control arrangement ofthe present invention; and

FIGURE 3 is a perspective view illustrating the cycle counting mechanismembodied in the control arrangement shown in FIGURES 1 and 2.

Referring to FIGURE 1 of the drawings, there is shown a refrigerationsystem incorporating the control arrangement of the invention. Thesystem includes an outdoor heat exchange coil or condenser 2 connectedby means of line 3 with the discharge side of a suitable refrigerantcompression mechanism, for example, a reciprocating type compressor 4.The gaseous refrigerant from compressor 4 flowing through outdoor coil 2is condensed by ambient air from outdoor fan 5. Liquid refrigerant fromcoil 2 flows through line 6, thermal expansion valve 8, and line 9 toindoor coil or evaporator 10. It is understood that other suitableexpansion devices, as a capillary tube, may be employed in place ofexpansion valve 8.

Liquid refrigerant in indoor coil 10 is vaporized by the stream of airfrom indoor fan 12, the cooled air being thereafter passed to the areabeing conditioned by suitable means (not shown). Vaporous refrigerantfrom coil 10 flows through line 13 to compressor 4. I

Referring to FIGURE 2 of the drawings, drive motor 16 of compressor 4 isconnected through contactor 19 across leads L L Leads L L are connectedto a suitable source of alternating current power (not shown). It isunderstood that a polyphase source of electrical power may be employedif the circuit is suitably modified.

Indoor fan motor 23 is connected by switch 25 across leads L L Outdoorfan motor 22 is connected by control relay switch 41 across leads L LControl relay 26 is series connected with temperature responsive switch27 across leads L L Switch 27 responds to temperature conditions of thearea being cooled.

Timer relay 48 is series connected by timer relay switch 49, system lowpressure switch 40, system high pressure switch 44- and control relayswitch 41 across leads L L Timer switch 32, when in the solid lineposition of the drawings, establishes a circuit bypassing timer relayswitch 49.

Switches 44, 40 are arranged to sense refrigerant pressure conditions indischarge and suction lines 3, 13, respectively. Switch 44 deenergizesthe compressor at a predetermined high refrigerant pressure in line 3while switch 4% deenergizes the compressor at a predetermined lowrefrigerant pressure in line 13. Other suitable protective devices, forexample, a compressor motor winding temperature sensor, a compressor oilpressure sensor, etc., may be employed with or in substitution of systemlow and high pressure responsive switches 40, 44, respectively.

Compressor contactor coil 53 is connected in parallel with timer relay48 through timer switch 32 and lockout switch 60. Cycle timer isconnected in parallel with coil 53. Timer 75 controls lockout switch 60,as will be more apparent hereinafter. Lockout switch 60, when moved tothe dotted line position of the drawings, closes contact 60' to completean energizing circuit to signal light 63.

Timer switch 61, when in the solid line position of the drawings,connects timer 35 through system low and high pressure switches 40, 44,respectively, and control relay switch 41 across leads L L Timer switch61, when moved to the dotted line position, closes contact 61' to placetimer 35 in series with timer relay switch 62 across leads L L Timerrelay switch 62 is opened by relay 48 upon energization thereof. Timer35 controls the positions of timer switches 32, 61, as will be moreapparent hereinafter.

Referring to FIGURE 3 of the drawings, shaft 74 of disc-like counter 76is rotatably positioned for movement on a suitable support member 77.Cooperating slot and pin means 78, 79, respectively, limit rotationaldisplacement of counter 76. Counter 76 is provided with a plurality ofcylindrical protrusions 80, 81 at spaced intervals circumjacent thecircumference thereof. Disc-like drive members 82, 83, operativelyarranged adjacent counter 76, have suitable projections 82', 83,respectively, engageable with protrusions 80, 81, respectively, ofcounter 76 to drive counter 76 in either a clockwise or counterclockwisedirection. Drive member 82, driven in a counterclockwise direction bytimer 35, moves counter 76 in the direction of the solid line arrow ofFIGURE 3 of the drawings. Drive member 83, driven by timer 75 in aclockwise direction, moves counter 76 in the direction shown by thedotted line arrow of FIGURE 3.

Projection 83 of drive member 83 is preferably resilient to preventjamming or overloading of timer 75 when counter 76 is fully reset.Projection 83 may, for example, be formed from spring steel. As will bemore apparent hereinafter, timer '75 is energized concurrently withcompressor drive motor 16. During that period, drive member 83, throughthe inter-engagement of projection 83' with protrusions 81, resetscounter 76 to bring pin 79 into abutment with end 78 of slot 78. Sincefurther counterclockwise movement of counter 76 is prevented by slot andpin means 78, 79, resilient projection 83 bends or deforms uponengagement with protrusion 81 and rotation of drive member 83 continuesunabated without overload of timer 75. Additionally, the resiliency ofprojection 83' prevents jamming of the apparatus should drive memberprojections 82', 83 both simultaneously engage counter 76.

The outer periphery of counter 76 is provided with a plurality of spacedrecesses or notches 94 therein. Recesses 94 cooperate with resilientfinger 95, fixedly secured to support member 77, to releasably retaincounter 76 in each of the several positions defined by each of recesses94 with finger 95.

Arm 89 of normally closed locking switch 68 is held by suitable biasmeans (not shown) in contact with the periphery of counter 76. Uponmovement of switch arm 89 in recess 84 of counter 76, switch 60 isopened to interrupt the power supply to contactor coil 53 and compressordrive motor 16.

Switch 60 is preferably provided with a resetting control, such as knob92, necessitating that switch 60 and counter 76 be manually reset priorto any resumption of the compressor operation. Knob 92, drivinglysecured to mounting shaft 74, permits manual resetting movement ofcounter 76 in a counterclockwise direction against the bias of resilientfinger 95. Signal light 63 gives visible indication when locking switch60 is opened.

Timers 35, 75 preferably operate at the same speed. Each revolution oftimers 35, 75 moves, by means of drive members 82, 83 respectively,counter 76 a distance equaling the space between the axes of adjacentprotrusions 80. The direction of movement of counter 76 may be eitherclockwise or counterclockwise.

With the several switches of the control circuit diagram in the positionshown in FIGURE 2 of the drawings, the refrigeration system is ready tostart on a demand for cooling. On a predetermined demand for cooling ofthe area being conditioned, switch 27 closes to energize control relay26. Relay 26 closes control relay switches 25 and 41. Switch 25completes an energizing circuit to the indoor fan motor 23. Switch 41completes an energizing circuit to outdoor fan motor 22.

Additionally, closure of switch 41 completes a circuit from lead Lthrough system low and high pressure switches 40, 44 respectively, andtimer switch 32 to lead 1 L to energize timer relay 48. Timer relay 48closes timer relay switch 49 to complete the bypass circuit of timerswitch 32. A second circuit is completed through control relay switch41, switches 40, 44 and timer switch 61 to energize timer 35.

Timer 35, after a short interval, moves timer switch 32 to close contact32' to complete energizing circuits to contactor coil 53 and timer 75.Contactor coil 53 closes contact 19 to complete an energizing circuit tocompressor motor 16.

At the expiration of a predetermined timed interval timer 35 moves timerswitch 61 to open contact 61" and close contact 61. Since switch 62 isopen, timer 35 is deenergized. Drive member 82 of timer 35 is in theposition shown in FIGURE 3 of the drawings.

Assuming that energization of the compressor drive motor 16 ismaintained for a relatively long period of time, drive member 83 oftimer 75 moves, through the interengagement of projection 83 withprotrusion 81, counter 76 in a counerclockwise direction shown by thedotted line arrow of FIGURE 3 to bring pin 79 into abutment with end 78'of slot 78. Further movement of counter 76 in a clockwise direction bymember 83 is prevented by pin and slot means 78, 79.

Upon satisfaction of the cooling demand imposed upon the system, switch27 opens to interrupt the energizing circuit to control relay 26 therebyopening switches 25 and 41. Switches 25, 41, when opened, interrupt theenergizing circuits to indoor and outdoor fan motors 23, 22,respectively. Switch 41 additionally interrupts the energizing circuitto contactor coil 53 and contact 19 opens to deenergize compressor drivemotor 16.

The circuit to timer relay 48 is interrupted. Timer relay 48 opensswitch 49 and closes switch 62. Switch 62 completes an energizingcircuit through timer switch 61 to timer 35. Following the expiration ofa determined timed interval, for example, five minutes, timer 35 movesswitch 32 to open contact 32' and close contact 32". Timer 35 is thendeenergized.

Drive member 82, operably connected to timer 35, moves, through theinteraction of projection 82' with an adjacent counter protrusion 80,counter 76 through one position in a clockwise direction. Counter 76 isnow in the solid line position shown in FIGURE 3 of the drawings. Thesystem is now ready to restart upon closure of switch 27.

If, during system operation, one of the switches 40, 44 opens inresponse to a malfunction as, for example, the opening of switch 44 at apredetermined high system pressure condition, the energizing circuits tocontactor coil 53 and timer relay 48 are interrupted and the compressordrive motor 16 is deenergized. Switch 62 closes to energize timer 35.Timer 75 is deenergized. Drive member 82 of timer 35 moves counter 76 ina clockwise direction through one position.

At the close of the determined timed interval, timer 35 moves switch 32to open contact 32' and close c011- tact 32". The compressor drive motor16 is restarted in the manner described heretofore.

If, on restarting of compressor drive motor 16, switch 44 reopens,compressor drive motor 16 is again deenergized. Drive member 82 of timer35 moves counter 76 an additional position in a clockwise direction.Followa ing the occurrence of a preset number of compressor motordeenergizations, switch arm 89 drops into recess 84 of counter 76 toopen locking switch 60. Switch 60 opens contact 60 to interrupt thepower supply to the compressor contactor coil 53 and closes contact 60"to complete a circuit to signal light 63. To restart the system, theknob 92 must be manually operated to reset counter 76.

It is understood that during each interval in which compressor drivemotor 16 is energized, timer 75 is similarly energized. Depending uponthe length of time compressor drive motor 16 is energized, drive member83 of timer 75 may effect movement of counter 76 in a counterclockwisedirection in opposition to the movement imparted to counter 76 by drivemember 82 of timer 35. Where, however, a sustained malfunction prevails,the period of energization of compressor drive motor 16 is so short thatmovement of counter 76 by timer 75 is without appreciable effect uponthe time required to actuate locking switch 60 and totally deenergizethe system.

While I have described and illustrated a preferred embodiment of myinvention, it will be understood that my invention is not limitedthereto since it may be otherwise embodied within the scope of thefollowing claims.

Iclaim:

1. In a refrigeration system including a compressor, the combination ofcontrol means operable upon a demand to energize said compressor;condition sensing means operable upon the occurrence of a predeterminedmalfunction to deenergize said compressor; timing means for preventingreenergization of said compressor by said control means for a timedinterval following each deenergization thereof; and means for countingthe number of compressor deenergizations responding to a predeterminednumber of compressor deenergizations for said timed interval to rendersaid control means inoperative.

2. The refrigeration system according to claim 1 in which said countingmeans includes a member movable in one direction through a presetdistance at each deenergization of said compressor, and means adapted toreset said counting means following energization of said compressor,said reset means being arranged to move said counting means member in anopposite direction through said preset distance following energizationof said compressor for said timed interval.

3. The refrigeration system according to claim 2 including drive meansengageable with said counting means member to move said counting meansmember in said one direction, said drive means being drivingly securedto said timing means.

4. The refrigeration system according to claim 3 in which said resetmeans includes a second timing means, and one-way drive means betweensaid counting means member and said second timing means effective uponoperation of said second timing means to move said counting means memberin said opposite direction.

5. The refrigeration system according to claim 3 in which said countingmeans includes a switch effective when actuated to prevent energizationof said compressor,

said switch including an actuating arm operatively disposed adjacentsaid counting means member, predetermined movement of said countingmeans member moving said switch arm to actuate said switch.

6. The refrigeration system according to claim 4 including means forenergizing said second timing means in response to energization of saidcompressor.

7. In a refrigeration system including a compressor the combination of,means controlling energization of said compressor in response torefrigeration system demand; condition sensing means operable upon theoccurrence of a predetermined malfunction to deenergize said compressor;means responding to a predetermined number of compressor deenergizationsto render said control means inoperative and prevent energization ofsaid compressor including a lockout switch effective when actuated torender said control means inoperable and a switch operator movable inone direction through a predetermined incremental distance at eachdeenergization of said compressor, said switch operator being adapted toactuate said lockout switch upon movement through a preset number ofsaid incremental distances; resetting means operable upon energizationof said compressor for a timed interval to move said switch operator inan opposite direction through said incremental distance; and meansadapted following predetermined movement of said switch operator in saidopposite direction to render said resetting means inoperable.

8. The refrigeration system according to claim 7 including first timingmeans adapted to prevent reenergization of said compressor for apredetermined time following each deenergization thereof, said firsttiming means including a drive member engageable with said switchoperator, said drive member being adapted upon operation of said firsttiming means to move said switch operator in said one direction throughsaid predetermined incremental distance.

9. The refrigeration system according to claim 8 in which said resettingmeans includes second timing means having a drive member engageable withsaid switch operator adapted upon operation of said second timing meansto move said switch operator in said opposite direction.

References Cited by the Examiner UNITED STATES PATENTS 3,053,057 9/1962McGrath 62158 3,054,271 9/1962 McGrath 62158 3,135,908 6/1964 Harris.

MEYER PERLIN, Primary Examiner.

1. IN A REFRIGERATION SYSTEM INCLUDING A COMPRESSOR, THE COMBINATION OFCONTROL MEANS OPERABLE UPON A DEMAND TO ENERGIZE SAID COMPRESSOR;CONDITION SENSING MEANS OPERABLE UPON THE OCCURRENCE OF A PREDETERMINEDMALFUNCTION TO DEENERGIZE SAID COMPRESSOR; TIMING MEANS FOR PREVENTINGREENERGIZATION OF SAID COMPRESSOR BY SAID CONTROL MEANS FOR A TIMEDINTERVAL FOLLOWING EACH DEENERGIZATION THEREOF; AND MEANS FOR COUNTINGTHE NUMBER OF COMPRESSOR DEENERGIZATIONS RESPONDING TO A PREDETERMINEDNUMBER OF COMPRESSOR DEENERGIZATIONS FOR SAID TIMED INTERVAL TO RENDERSAID CONTROL MEANS INOPERATIVE.